Ncert Exercises & Solutions

Which of the following are characteristics of thermosetting polymers?

1. Heavily branched cross-linked polymers

2. Linear slightly branched long-chain molecules

3. Become infusible on molding so cannot be reused

4. Soften on heating and harden on cooling, can be reused

(a, c)

Thermosetting polymer

(i) These are cross-linked or heavily branched molecules.

(ii) These on heating undergo extensive cross-linking in molds and become infusible

(ii) These cannot be reused.

(iv) Examples are bakelite, urea-formaldehyde resin.